Want to Explore the Universe From Home? Here’s How

Do you want to explore the universe from home? here’s how

By far the best thing about my job as an astronomer are those rare moments when I get to see beautiful distant galaxies, whose light left them behind millions to billions of years ago. It’s a combination of sheer awe and scientific curiosity that gets me excited about “galaxy hunting”.

In today’s astronomy, much of our work processes vast amounts of data by writing and executing programs to work with images of the sky. One drawback to this is that we don’t always have that “hands-on” experience of looking at every square inch of the universe as we study it. However, I’m going to show you how I get my wonder of looking at galaxies that only a select few people will have ever seen, until now.

in only our observable universe we estimate that there are over 2 trillion galaxies!

Galaxies at your fingertips

Just a few decades ago, after a long, cold, and lonely night of observation, astronomers had to laboriously examine photographic plates. In the 21st century, we have access to information anytime, anywhere via the Internet.

Automated telescopes and surveys now provide us with so much data that we need machines to analyze it. In some cases, human eyes will only look at what the computers find interesting! Huge amounts of data are hosted online, waiting to be admired for free.

Go online for a universe atlas

Aladin Lite is one of the best online tools available for looking at our universe through the eyes of many different telescopes. Here we can scan the entire sky for hidden galaxies and even decipher information about their stellar populations and evolution.

Let’s begin our universal tour by searching for one of the most visually stunning galaxies out there, the Cartwheel Galaxy. In the Aladin interface, you can search for both an object’s popular name (such as “cartwheel galaxy”) and known coordinates. The location is centered in the interface.

The first image of the Cartwheel Galaxy we see is from optical imaging by the Digitalized Sky Survey. The colors we see represent different filters of this telescope. However, these are fairly representative of what the galaxy would look like with our own eyes.

A general rule of thumb as an astronomer is that “color” differences within galaxies are the result of physically different environments. It’s important to note that things that look blue (shorter wavelengths) are generally hotter than things that look red (longer wavelengths).

In this galaxy, the outer ring appears more blue than the center red. This could indicate star formation and star activity in the outer ring, but less so in the center.

To confirm our suspicions of star formation, we can choose to look at data from different studies at different wavelengths. The formation of young stars releases enormous amounts of UV radiation. By changing the survey to GALEXGR6/AIS, we now only look at UV wavelengths, and what a difference that makes!

The entire center portion of the galaxy seems to “disappear” from our view. This suggests that this area is likely home to older stars, with less active ones stellar nurseries

Aladin is home to 20 different surveys. They provide imaging of the sky using optical, UV, infrared, X-ray and gamma rays.

When I roam the universe looking for interesting galaxies, I generally start in optical and find the ones that seem interesting to me. Then I use the different studies to see how the images change when I look at specific wavelengths.

Universal Where’s Wally

Now that you’ve had a crash course in galaxy hunting, let the game begin! You can spend hours exploring the incredible visuals and finding interesting looking galaxies. I recommend looking at DECalS/DR3 images for the highest resolution and detail when you zoom in further.

The best method is to just drag the aerial atlas around. If you find something interesting, you can find all the information we have about it by selecting the target icon and clicking on the object.

To aid you in your galactic expedition, here are my favorite finds of the different types of objects you might see.

spiral galaxies usually have a central rotating disk with large spiral “arms” that bend out of the denser central areas. They are incredibly beautiful. Our own Milky Way is a spiral galaxy.

Elliptical Galaxies are largely featureless and less “flat” than spirals, with stars sometimes almost occupying a 3D ellipse. These types of galaxies tend to have older stars and less active star-forming regions compared to spiral galaxies.

Lenticular Galaxies appear as cosmic pancakes, quite flat and unmarked in the night sky. These galaxies can be seen as the “in-between” of spiral and elliptical galaxies. Most star formation has stopped, but lenticular galaxies can still contain significant amounts of dust.

There are also other amazing types of galaxies, including: mergers and lenses, waiting for you to find them. I’d love to see what great stuff you find on Twitter at @sarawebbscience.


Sara WebbPostdoctoral researcher, Center for Astrophysics and Supercomputing, Swinburne University of Technology

This article was republished from The conversation under a Creative Commons license. Read the original article† This article has been updated since it was first published.

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